Last summer, the Center for Biological Diversity filed a petition with the U.S. Fish and Wildlife Service requesting that the grizzly bear, which is today found mostly in Alaska and Yellowstone National Park, be reintroduced into regions where it once thrived. Among the habitats proposed by the environmental organization was California’s Sierra Nevada. The last grizzly in California was spotted in 1924, and the effort to return the animal, which is emblazoned on the state flag, elicited both excitement and fear. But mostly fear. A charging ursus arctos horribilis can reach speeds of 30 miles an hour. It weighs up to 1,700 pounds. One resident of the Sierras, informed of the proposal by a reporter, put her hand to her mouth in shock. Another said that reintroducing the grizzly “would be like bringing back Tyrannosaurus rex.” After I read about the petition in the newspaper, the potential return of the grizzly stuck in my head for weeks, in part because it seemed so fantastical. Could we really bring back such large animals and set them loose in a land they hadn’t known for nearly a century? And if we did, what would happen?
These are the sorts of questions that consume Beth Shapiro, an evolutionary biologist who takes the fantastic to a higher level with her new book, “How to Clone a Mammoth: The Science of De-Extinction.” Shapiro, an expert in “ancient DNA,” won a MacArthur Award in 2009 at the age of 33, and she and a band of pioneering scientists have been on a mission to “de-extinct” animals, a project that she argues has “great potential” in the fight to conserve existing species and habitats.